World ethanol production is expected to experience double-digit growth in the next years. Much of the growth is expected to occur in the United States where, with the current pace of expansion, the United States will be the leading producer of ethanol in the near future.
In the Untied States, ethanol is made almost exclusively from corn. As of December 2006, 16% of the United States corn crop was being used to displace 3% of the nation's annual gasoline consumption. The US government has a stated goal of reducing its dependence on foreign oil by 20%. If this reduction were to come entirely from corn based ethanol it would use up the nation's corn crop. As a result there has been a considerable amount of research in the production of ethanol from other sources.
Government and private sector scientists have been working on ways to produce ethanol from cellulosic material. Ethanol produced from switch grass, mixed prairie grasses and woody plants grown on marginal land could potentially meet the growing demand for green fuel. One leading company has targeted the collection of corn cobs—a current waste material—as a cellulosic ethanol feed stock.
Corn Cobs have been used in the manufacture of a great number of items in the past, however in the last 10 years interest in corn cobs has waned. There is currently no commercially available equipment to collect corn cobs and a very small number of people that have built equipment to collect cobs themselves. The residue from the corn harvesting process after the shelled corn kernels have been extracted in the combine harvester includes the cobs and the remaining crop residue which is called herein “stover”.
Current methods to collect cobs are very crude. A small number of farmers have built equipment to be mounted or pulled behind their combines.
Problems with existing technology:
Heavy cart behind combine—17000 lbs—combines are designed to pull a maximum of 10000 lbs;
Cleaning methods are not sophisticated enough to properly collect all cobs so there is a large amount of wasted cobs;
The operator has to stop harvesting to empty the cart.
One solution includes a collection tank mounted above a combine's grain tank—making the additional load too high and too heavy for current combines; this will be very difficult to be made commercially available with the diverse number of combine designs manufactured over the last 20 years.
The following prior patents are relevant to this field:
U.S. Pat. No. 6,358,141 Stukenholtz issued Mar. 19, 2002 discloses a collection system on a combine harvester with at least two on-board bins and appropriate cob separation equipment is detailed on the harvester itself.
U.S. Pat. No. 5,941,768 Flamme issued Aug. 24, 1999 discloses a cob collection unit which is pulled behind the combine to collect on a first conveyor all the residue discharged from a combine. A separation unit behind the conveyor includes a second conveyor and utilizes a fan to suck the stover off of the cobs as they are released from the top of the second conveyor and to blow the stover back onto the field. The heavier cobs are conveyed by a third conveyor belt up into the top of a collection tank. A fan housing is located at the rear end of the first conveyor, and the residue is sucked through the fan inlet and blown out of the fan outlet.
U.S. Pat. No. 5,256,106—Shrawder—A combine is improved to reduce corn cobs to usable segments by adjusting clearances and a conveyor is added behind the cleaning shoe.
U.S. Pat. No. 4,892,505—Shrawder—A combine is improved to reduce corn cobs to usable segments by adjusting clearances and a conveyor is added behind the cleaning shoe.
U.S. Pat. No. 4,600,019—McBroom—A sieve is designed for a combine to allow the passage of corn and corn cobs through.
U.S. Pat. No. 4,548,213—Phillips—A corn cob sieve is shown with its geometry designed to allow passage of corn and corn cobs through.
U.S. Pat. No. 4,188,160—Corbet—A residue saver is shown that is mounted behind the combines sieve. The residue saver can be adjusted to save all materials or only large residue such as corn cobs. The saved residue is blown into a trailing wagon.
U.S. Pat. No. 3,680,291—Soteropulos—A corn harvesting machine is depicted which harvests and chops up both the corn and the stover. The grain is stored in a tank, and the stover is stored in a second tank or spread back on the ground.
U.S. Pat. No. 3,640,055—Looker—A two row self propelled corn picker is shown with a blower mounted behind the corn header to blow loose material out of the side of the machine. The husks are blown away as they drop from an elevated picker head. Side panels project upward and outward from the sides of the conveyor and a specially constructed blower is mounted above the bottom conveyor for directing streams of air laterally. As the crop slides down the side panels it is cleaned of trash with counter flowing streams of air.
U.S. Pat. No. 2,822,811—Slavens—A corn husking machine is detailed where the corn ear is picked and husked. A fan is used to blow and separate the husks from the ear corn.